1. Field of the Invention
The present invention relates to a method of fabricating a holographic contact lens, and in particular to a contact lens capable of generating a holographic impression of a person's eyes through the lenses and changing colors when looking from a different angle, and a method of fabricating the same.
2. The Related Art
Contact lenses are now more than ophthalmic lenses normally used for correction of impaired vision, such as nearsighted, farsighted, bifocal, or multi-focal. New contact lenses are targeted at the younger generation who wears them to enhance aesthetic or ornamental effects, such as color lenses and magic lenses.
People initially wear the colored contact lenses only for parties, or as part of the costume for stage performances, but through the recent innovations in lens-making, many people now wear the colored contact lenses because they want to change the color of their eyes to make them look more attractive. These people wear them regularly and usually for the greater part of the day.
However, a recent study on the habits of wearing colored contact lenses as it relates to the visibility, viewing brightness and comfort of the persons wearing contact lenses has raised some health concerns, as they suggested that persons constantly wearing the contact lenses in situations of inadequate lighting or at night time might permanently impair their eyesight, in addition to other findings that also said persons wearing contact lenses to do physical exercises or drive a car are likely to inflict eye injuries.
Normally, the pupil of the human eyes will grow larger or become smaller in response to the intensity of light received. The diameter of the pupil can grow to almost 6 mm at night. Since the peripheral area of most colored contact lenses are opaque and dyed, and the diameter of the light transmission zone of these colored contact lenses is between 4 to 6 mm, the size of the pupil can only grow as large as the light transmission zone of the contact lens which are disposed in front of a person's eyes. A German report also confirmed that long-time wearing of the colored contact lenses at nighttime or in inadequate lighting often results in permanent impairment to the eyesight and visibility.
The majority of lens makers of colored contact lenses have used some kinds of chemical colorants, which will hurt the eyes, in making the contact lenses. Some unscrupulous lens makers even use non-approved colorants or those never been field tested to reduce their product costs or to increase the range of colors of the contact lenses. Permanent impairment could be inflicted even for one-time users of such disposable contact lenses.
Also, conventional color contact lenses, or so-called cosmetic contact lenses, have color patterns imprinted on the surface of the contact lenses using chemical colorants. In general, these cosmetic contact lenses can only provide a planar impression, unlike holographic contact lens that can produce a stereoscopic effect and changing colors of a person's eyes when looking through the lenses from different angles.
This holographic contact lens is the result of using a hologram technology, which has brought about new ideas to the making of contact lenses. The hologram technology has been used in many applications such as laser CD labels, turntables or decorative boards. The hologram technology is to use the recording of multiple light interference lines on a light exposure film to be transferred onto a lens-making mold for the fabrication of the holographic contact lenses. One of the more commonly used methods is to use a photo resist agent to record the light interference lines, and, after an exposure and development process, an undulating layer is created on the surface of a molding board. Another method is to employ a computer emulation program to reproduce the light interference pattern directly on the molding board. Once the molding board is prepared, the lens-making molds can be produced in large quantity using press forming or roll pressing.
This holographic contact lens makes use of the diffraction grating principles to impart colors on the eyes of a person wearing the contact lenses, without chemical colorant or dyes, and also to produce a stereoscopic effect and changing colors when looking through the lenses from different angles, therefore such contact lens is much healthier to use as it apparently does no harm to the person's eyes even after prolonged use.